1. Field of the Invention
The present invention relates to a flexible mat comprising inorganic fibers useful as a fire barrier material.
2. Description of Related Art
Ceramic fibers are typically heat resistant and maintain dimensional stability even at high temperatures (e.g., 500.degree. C. and above). Such fibers are useful, for example, for flame and fire resistant applications such as furnace blankets and gaskets, heat shields, and fire walls. Although woven fabrics of ceramic fibers are known, their area weights, which typically range from about 220 grams/meter.sup.2 to about 1000 grams/meter.sup.2, make them undesirably heavy for many flame and fire resistant applications.
Nonwoven fabrics of ceramic fibers are also known; however, because ceramic fibers are typically brittle, it is generally difficult to produce such nonwoven fabric constructions with sufficient integrity to withstand normal handling (including that associated with installation). Bonding the fibers together at their points of intersection helps overcome this problem. Bonding methods include sol-gel impregnation, chemical vapor deposition, thermal treatment, stitchbonding, needle punching, or using a scrim to hold the fibers in place. Although such bonding methods can provide nonwoven fabrics useful, for example, in filtration applications, as catalytic converter mounting mats, and as thermal and acoustic insulation, the fabrics are typically relatively heavy, as compared to light weight nonwoven fabrics that include polymer or cellulose-derived materials. Such fabrics are used, for example, as surgical dressings, napkins, diapers, and clothing. Although these fabrics are lighter weight and typically more flexible, they usually do not have the flame and fire resistant characteristics necessary for use in fire barrier mats.
Therefore, a challenge remains to provide a flexible nonwoven mat having good flame barrier characteristics that is light in weight, strong, flexible, and preferably retains its integrity after exposure to high temperatures.